Results: A total of 646 patients were randomized and treated with ABA (n=318) or ADA (n=328) on background MTX. Patient characteristics were balanced. A similar proportion of patients achieved a HAQ-DI response from baseline to year 1 (60.4% patients in the ABA arm vs. 57.0% patients in the ADA arm). Improvements in patient pain (mean% ± SE) were 46.5 ± 4.2% vs. 35.6 ± 4.1% at 6 months, and 53 ± 6.1% vs. 39.2 ± 6.0% at 1 year for ABA and ADA, respectively. Improvements in PtGA were 40.2 ± 7.3% vs. 27.6 ± 7.2% and 46.1 ± 3.5% vs. 41.2 ± 3.4% for ABA and ADA at 6 months and 1 year. Fatigue decreased from baseline by -22.4 ± 1.5% vs. -19.9 ± 1.5% at 6 months, and -23.2 ± 1.5% vs. -21.4 ± 1.5% at 1 year for ABA and ADA respectively. Improvements in all domains of the SF-36 including PCS and MCS observed at 6 months were maintained at 1 year (Figure). For RAPID3, the ABA and ADA-treated groups demonstrated improvements (mean ± SE) of -2.7 ± 0.1 vs. -2.5 ± 0.1 at 6 months and -2.9 ± 0.1 vs. -2.7 ± 0.1 at 1 year.

Conclusion: In this first head-to-head comparison, subcutaneous abatacept demonstrated significant improvements with similar kinetics of response in patient-reported outcomes and HRQoL measures over 1 year which were comparable to adalimumab.